What are the current trends? For example, when DD was a baby, most people started solids at 4 months, but around here the trend was to wait until at least 6 months. I read a few years ago that earlier actually was better because it caused fewer allergies (I'm not saying it's true, I don't know, just saying what I read). What is the trend now? Back to 6+ months or what?

Somebody school me on all the "baby" rules that may have changed since my DD was a baby.

I have no idea!! It's all so variable depending on what 'parenting theories' you want to ascribe to.

My ped did let me know that there was a correlation between babies who started solids between 4-6 months and a lower rate of diabetes I think. It doesn't matter WHAT the first food is, like you don't have to start with rice cereal and work up to veggies, you can start with whatever appeals to baby. Also, all babies are recommended to take vitamin D supplements now, some parents do it, some don't. There is a rising trend in non-vaccinating, as well a selective and delaying vaccinations. Many people seem to be generally anti CIO in my area as well. No honey til after 2 as babies can potentially get botulism. Crib bumpers in general are recommended against in babies under a year now as well as any blankets, stuffed animals, or other fluffy things in the crib. Babies are encouraged to sleep on their backs to reduce SIDS rates (don't know how old that is...). The AAP now recommends rear facing car seats until at least age 2, and harnessing forward facing as long as possible. There's so many potential things!!

What are the current trends? For example, when DD was a baby, most people started solids at 4 months, but around here the trend was to wait until at least 6 months. I read a few years ago that earlier actually was better because it caused fewer allergies (I'm not saying it's true, I don't know, just saying what I read). What is the trend now? Back to 6+ months or what?

Somebody school me on all the "baby" rules that may have changed since my DD was a baby.

My dd is almost the exact same age as yours, and all the research I did supported waiting until 6+ months (when baby can sit unassisted and no longer has a tongue thrust reflex and the gut is more mature). Because infants have an open gut, you actually increase the risk of allergies if you introduce solids too early. http://kellymom.com/nutrition/starti.../delay-solids/

I don't know what the "trends" are, but it always seemed like common sense to me that if a baby has to eat processed baby food, s/he is not ready for food. We started with whole foods--soft chunks of banana and avocado--when dd seemed physiologically ready. We never bought any commercial baby food.

The change in the allergy recommendations has to do with when you introduce ALLERGENS, not when you introduce solids. This is something I'm actually pretty up on, since dd has severe food allergies. They used to say to delay allergens, but now they say that smaller amounts introduced earlier are better than big amounts introduced later.

The trend is going more towards CLW (child led weaning). Letting the child show interest in real table foods, like cooked/really soft foods between 9-12 months instead of purees.
As PP mentioned, extended carseat rear-facing, selective vaccinating and leaving all children intact are becoming more popular.

We did selective vax with DD and will with this peanut as well. We didn't start DD on solids till 6 months. The breastfeeding recommendations are the same as they were with her. The rear-facing carseat until 2 was just picking up speed about the time DD was around 18 months old.

Let's see no honey till 2 years is new, it was 1 year when Molly was a baby and toddler.